lol thats not gonna happen, its stored on your computer and on the steam cloud, which IW don't have access to afaik, and i doubt steam will go there.
Anyways @ OP, Try this it should still work ...
Delete Steam’s Local Player Stats – when clicked, the following five files are deleted in order to reset the user’s rank to zero (rank level 1) in the Steam Cloud:
\Steam\SteamApps\common\call of duty modern warfare 2\players – two .stat files
\Steam\userdata\(some numbered folder)\(some numbered folder)\remote\ – two stat files
\Steam\userdata\(some numbered folder)\(some numbered folder) – remotecache.vdf
Note: in order for stats to be reset using the file deletion method, Steam must be running and the game must not be running.
After you do this join a game and rank up a few levels then exit the game and let steam sync the stats.